In general, an orthopedic foot splint is useful in correcting bone deformities, particularly in children, by holding the patient's feet at an appropriate corrective angle. Thus, if a patient's feet are abnormally toed-in, it is recommended that the patient wear a splint for a specified period which will hold the feet in a corrective toed-out position. A common type of prior art device, as disclosed in U.S. Pat. Nos. 2,920,620 to Rogers; 4,040,416 to Zentman; and 4,008,129 to DiGiulio, includes a pair of shoes mounted on a flat bar. The shoes in these devices are adjustable on the bar to provide a variety of different toe-in and toe-out angles, but are not otherwise adjustable. Unfortunately, these prior art devices are extremely uncomfortable to the patient as they maintain the feet in almost rigid positions. Even the patent to Zentman which includes a flexible spacer bar to allow a slight amount of vertical movement does little to alleviate this problem. In addition, the patient cannot move except by hopping, which is dangerous and perhaps impossible for young children to perform.
To overcome this almost total lack of mobility and extreme discomfort, prior art devices have been proposed which do allow some movement as well. For instance, in U.S. Pat. No. 2,963,020 to Moran, a device is disclosed which comprises a separate member attached to each shoe of the patient which members are connected by parallelogram links. These linkages are pivotally attached to each shoe member and this allows movement of the feet both upwards and downwards, and forwards and rearwards. In addition, the length of the linkages is manually adjustable. U.S. Pat. No. 3,487,829 to Barnett also discloses parallelogram links connecting shoe engaging members. In this device, the parallelogram links are attached to the shoe engaging members by ball and socket joints. This device also allows the feet to move forwards and backwards, and upwards and downwards, as well as allowing the ends of the shoes to tilt upwards or downwards somewhat.
In U.S. Pat. No. 4,249,523 to Bidwell, an adjustable orthopedic foot splint to which a pair of shoes are attached is disclosed which maintains a desired angle between the shoes but which otherwise allows virtually full freedom of movement of the shoes. While the foot splint disclosed in the patent is a vast improvement over the prior art types of foot splint mentioned above, some users additionally have a problem with one foot (usually the left foot) moving directly in front of the opposite foot while walking. This is especially a problem for infants as they first learn to walk.